As the bus was towed away from the scene in nearby Irving, the video clearly showed one tire that was blown out. Some passengers told NBC 5 Dallas-Fort Worth they heard a loud popping sound before impact. That could have been a tire blowout.

"We've heard stories passengers heard a loud pop so we will be looking at tire safety and looking at the equipment on the bus itself," said former Department of Transportation official Brigham McCown.

Casino Trip Organizer Killed in Bus Crash

Family friends described Sue Taylor, who went by the name "Casino Sue," as a "firecracker" of a woman. (Published Friday, April 12, 2013)

But others passengers said they did not hear or see anything wrong in the seconds before the crash.

The bus driver, Loyd Reive, has been working as a commercial driver for nearly 20 years, according to his family.

Charter Bus Driver's Family Says He Was a Good Driver

The family of Loyd Rieve, the man behind the wheel of the charter bus crash, spoke to NBC 5 about Rieve being a safe driver. (Published Friday, April 12, 2013)

Casino trip organizer Sue Taylor, 81, of Hurst, and Paula Hahn, 69, of Fort Worth, died in Thursday's crash, the Texas Department of Public Safety said.

Family friends described Taylor, who went by the name "Casino Sue," as a "firecracker" of a woman.

"We're devastated," Janet Denham said.

Her friends said Taylor often planned casino trips and would entertain her guests with games during the road trips. Her daughter told NBC 5 that her mother had been organizing the trips for 10 years.

Information from area hospitals had 13 patients still receiving treatment at Parkland, three at Baylor Irving, one at Baylor Dallas, and one at Methodist. All patients were treated and released at the UT Southwester St. Paul Medical Center. Las Colinas Medical Center did not respond to calls for updates on the seven patients transported there.

"After hearing what I've heard and seeing what I've seen in person, I feel extremely fortunate to be virtually injury-free -- a few scrapes, whatever," Risik said. "Other than that, I feel very lucky."

Deadly Texas Bus Crash Coincides with Safety Crackdown

Thursday's deadly crash happened in the middle of an aggressive push by federal regulators to shutter unscrupulous carriers and ramp up safety inspections.

The Federal Motor Carrier Safety Administration has shut down more than a dozen private bus companies — nearly half of which it deemed "imminent hazards" — over the past couple months. Last week, the agency announced it was deploying a team of more than 50 safety investigators throughout the country to conduct a wider examination of "higher risk" carriers, including many small charter operations. The FMCSA also asked local police to join the crackdown by boosting traffic enforcement.

The inspection teams headed out into the field on April 1, with orders to target 250 companies with lackluster safety records, according to the American Bus Association, a trade group whose officials were briefed by federal authorities.

Among the carriers already shut down by the FMCSA was Fung Wah, a popular discount bus service between New York City and Boston that had a history of crashes and safety violations.

It's not clear whether the owner of the bus that wrecked Thursday, Cardinal Coach Line, would have been targeted in the crackdown had the crash not happened. According to FMCSA's online record system, Cardinal Coach Line was given a "satisfactory" safety rating in 2009. In the past two years, none of the company's five buses has been in a crash, the records say. But the company's two inspections over that period found violations that resulted in putting a bus and/or or a driver out of service.